Bound Water Content of Vegetative and Spore Forms of Bacteria

Abstract

The authors have previously shown that the total water content of the vegetative cells and the spores of Bacillus subtilis, Bac. megatherium and Bac. mycoides is essentially the same. The present paper shows that the water existing in a free or unbound state, as detd. by the cryoscopic method, is greater in the vegetative cells than in the spores of the 3 spp. of bacteria mentioned above. The theory is advanced that the bound water in the spores is not involved in the coagulation of the protein due to heat and that, while the total moisture content of the 2 types of cells is the same, the difference in free water might account for the observed difference in the heat-resistance of the cells.